let count: number
count = 100
count = 200

let count1: 100
// count1 = 200

// 2. 字面量类型的应用
// 字面量联合类型
// let gender: string
// gender = '男'
// gender = '女'
// gender = '泰国'

// 改进
type Gender = '男' | '女'
let genter: Gender = '男'
genter = '女'
// gender = '未知'

// 什么场景会用到字面量联合类型?
// 性别, 学历, 政治面貌....

// 3. 思考
let str1 = 'my name is jack'
str1 = '2121'

const str2 = 'my name is rose'
// str2 = '22121'


export { }